There is no need to differentiate "kind" if you are using regular web hosting. However, there may be cases where you want to host only HTML for exploration or share only JavaScript for code sharing. But in the current relay implementation, it is not possible to restrict inserts based on the value of the "m" tag. Therefore, to implement relays like the ones mentioned earlier, you would need to either develop custom middleware or modify the relay. Hostr aims to provide diversity without altering existing implementations as much as possible, which is why this specification is in place.